Global Biodiversity


The big picture: Earth’s systems and humans interact
- Biodiversity can be measured at many scales
- maintaining high biodiversity has huge benefits
- Conservation biology focuses on the population level
- small populations have genetic problems
- Global Change is occurring at unprecedented rates
- Yes, change has occurred over Earth’s history
- No, it has never occurred this quickly
- Are we in a new mass extinction?

What is biodiversity?
- Level 1: Genetic Diversity
- within and among populations
- loss reduces adaptive potential
- Level 2: Species Diversity
- number of species in a system
- local or whole extinctions possible
- Level 3: Ecosystem Diversity
- variety of ecosystems on Earth
- provide services to living things

How do we measure biodiversity?
- Genetic Diversity: alleles in populations
- what happens when a population disappears?
- Species Diversity
- how many species?
- how even are the species?
- roles of dominant, keystone & rare species
- Ecosystem Diversity
- what services does an ecosystem provide?
- are the abiotic variables changing?

The selfish view: what does biodiversity provide us?
- Moral code: Each species belongs
- what happens when a species becomes locally extinct?
- Practical benefits for all 3 biodiversity types
- genetic diversity a tool for medicines
- diversity feeds, clothes and houses humans
- Ecosystem Services to humans
- raw goods
- health and well being
- regulation of air, water, etc

Why is biodiversity changing?

- Human activities threaten biodiversity
- Threats posed by humans fall into 4 categories
- habitat loss
- species introductions
- over-harvesting
- global change
- Landscape change by humans is largest threat
- nearly all land surface has been altered
- causes fragmentation or loss of habitat
Introduced species and over-harvesting


How does conservation biology work?
- Small populations are the most vulnerable
- population getting pushed to extinction
- Small populations vulnerable to inbreeding
- genetic issues of non-random mating
- Small populations vulnerable to genetic drift
- Goal: Maintain genetic diversity

How does conservation biology work?
- Detect downward trends in population sizes
- may be a large population
- Prioritize the factors causing decline
- habitat loss or climate change
- What are the environmental needs of the species?
- What causes the decline
- How do we stop it?

Landscape conservation: Building habitat corridors


Global Change: What is in a name?
- Climate change:
- more than just temperature
- mostly related to post 1950’s
- Global change:
- e.g. nutrient cycles, biodiversity, land use, sea level rise, ice loss

Global Change: Climate change
- Climate change is strongly related to the chemistry of the atmosphere
- greenhouse gas effect
- CO2, CH4, NOx & H2O
- Greenhouse gases intercept and absorb radiation
- more greenhouse gases = higher temperatures
- Burning of fossil fuels has increased atmospheric CO2
- makes biosphere warmer
- impacts weather and climate

Greenhouse effect is a natural process!

Global Change: Nutrients
- Humans move nutrients around too much
- mostly to support agriculture
- disrupts natural cycling
- Ecosystems may reach critical load of a nutrient
- nutrient cannot be taken up by plants
- excess N on crops, leaches to aquatic systems
- excess N impacts area not intended


Global Change: Toxins


Global Change: What can we do?
- We cannot save all habitats
- which patches are most crucial?
- Sustainable development
- better engineer man-made ecosystems
- food security while reducing nutrient/chemical impacts
- food security while maintaining ecosystem services
- Curb global emissions
- can we do it?
- technology?

Future of the Biosphere
